Damper

ABSTRACT

To substantially increase a slide torque of a fitting type damper formed by press-fitting, an elastic body of a rubber-like elastic material is located between a hub and a massive body from either direction of a shaft. Polymethylene-polyphenyl-polyisocyanate is interposed as a non-slide agent between hub including a metallic part at a boundary of an elastic body or between a massive body including a metallic part at an opposite boundary of the elastic body.

This is a Divisional of application Ser. No. 09/140,320 filed Aug. 26,1998 now U.S. Pat. No. 6,171,194.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a damper, and more particularly, to atorsional damper for absorbing torsional vibration occurring in arotation driving system such as a crankshaft of an internal combustionengine, or the like.

2. Description of the Related Art

Conventionally, a torsional damper connecting a hub with a massive bodyvia an elastic body of a rubber-like elastic material has been wellknown, and as a kind of it, a fitting type torsional damper has beenknown which is formed by press-fitting an elastic body of a rubber-likeelastic material into a space between the hub and the massive body fromeither direction of the shaft.

However, since this fitting type torsional damper is not bonded byvulcanization adhesion, there is such an inconvenience that slidesoccurs, at a time of a heavy load condition, between the hub comprisedof metallic parts and the elastic body or between the massive bodycomprised of metallic parts and the elastic body in the direction of therotation.

To increase (improve) a slide torque for preventing this slide,mechanical methods have conventionally been employed such as a fittingsurface of the hub or the massive body is treated by shot-blasting orthe like to give these surfaces unevenness, or stickiness is provided ona surface of the elastic body, etc. However, either of these methods hashad an insufficient effect so far.

For example, as is described in Japanese Patent Tokkai Sho 60-141532,adhesives such as a chlorinated rubber as a main ingredient is appliedto a place between the hub and the elastic body or a place between themassive body and the elastic body. However, a conventional adhesive hasan insufficient effect in an adhesive strength, or to the contrary, anadhesive strength is so tight that ill influence on other propertiessuch as durability or the like tend to come out.

In view of the above-mentioned aspects, an object of the presentinvention is to provide a fitting type damper permitting tosubstantially increase a slide torque, especially, to provide a fittingtype damper permitting to substantially increase a slide torque atinitial stage as well as a slide torque even after heat-aging, endurancetests, or the like.

Another object of the present invention is to provide a process formanufacturing a fitting type damper permitting a substantial increase inslide torque at an initial stage as well as a slide torque even afterheat-aging, endurance tests, or the like.

SUMMARY OF THE INVENTION

In order to achieve the above objects, the damper according to thisinvention, in a fitting type damper formed by press-fitting an elasticbody of a rubber-like elastic material between the hub and the massivebody in either direction of the shaft, haspolymethylene-polyphenyl-polyisocyanate as a non-slide agent which isinterposed between said hub comprised of metallic materials and aboundary of said elastic member or between said massive member comprisedof metallic materials and a boundary of said elastic member.

It is an object of the present invention to increase a slide torque by achemical method instead of a conventional mechanical method mentionedabove and to increase a holding power of a metallic part and an elasticbody by interposing a non-slide agent between the metallic parts and theelastic body (rubber). As a result of our intensive research to obtainan excellent sliding torque and also to avoid a deteriorating influenceon other properties, polymethylene-polyphenyl-polyisocyanate hasspecifically been determined as a kind of the non-slide agent.

Polymethylene-polyphenyl-polyisocyanateis is shown by the followingformula:

Wherein n≧0.

Polymethylene-polyphenyl-polyisocyanate is interposed between the hubcomprised of metallic parts and the boundary of the elastic body, orbetween the massive body comprised of metallic parts and the boundary ofthe elastic body and non-slide effect can be obtained respectively.Another applying method is that polymethylene-polyphenyl-polyisocyanateis interposed both between the hub comprised of metallic parts and theboundary of the elastic body and between the massive body comprised ofmetallic parts and the boundary of the elastic body, and the non-slideeffect can be obtained both at the place between the hub and the elasticbody and between the massive body and the elastic body at the same time.

The damper of the present invention is obtained by the followingprocedures:

a. Applying a non-slide agent havingpolymethylene-polyphenyl-polyisocyanate onto at least one of a surfaceselected from a group of an outer peripheral surface of the outerperipheral side of the hub or an inner peripheral surface of the massivebody or a surface of the elastic body,

b. Drying the hub or massive body or the elastic body so as to preventfrom dripping of polymethylene-polyphenyl-polyisocyanate,

c. Press-fitting an elastic body between the hub and the massive body toform an assembly,

d. Cleaning the assembly in a solvent to remove dusts, and

e. Heating the assembly to react the none-slide agent.

Applying process and press-fitting process is essential for the presentinvention. But drying, cleaning and heating processes can be eliminatedfrom the processes, for example, in order to cut the cost of theproduction.

Applying the polymethylene-polyphenyl-polyisocyanate onto the surface ofthe hub or the massive body can be achieved by spray coating, brushcoating or immersion coating or the like. Thepolymethylene-polyphenyl-polyisocyanate can be applied onto the hub onlyor the massive body only or both of these metal parts, or onto theelastic body only or both of the elastic body and the metal parts. Andthen the elastic body is press-fitted into the space between the hub andthe massive body to assemble a damper.

It is essential that the non-slide agent comprisespolymethylene-polyphenyl-polyisocyanate. Other chemical agents orsolvents may be added into polymethylene-polyphenyl-polyisocyanate sofar as substantial non-slide effect of the present invention can beobserved.

Referring to the heating process, it is not necessarily to take thisprocedure because the reaction ofpolymethylene-polyphenyl-polyisocyanate occurs slowly under even at roomtemperature. But it is desirable to warm the assembly to accelerate thereaction speed. The desirable temperature of the heating process is notlower than 70° C. because the reaction speed is considerably slow underthis temperature, and not higher than the temperature that the elasticmaterial can be decomposed. If NBR (acrylonitrile butadiene rubber) isused for the elastic material, for example, the desirable heatingtemperature is around 120° C. and caution must be paid to keep thetemperature not more than 170° C. to avoid the decomposition of therubber.

Almost all rubber like materials may be used in the present invention.Blend rubber can also used. NBR, EPDM, VAMAC, EPDM/VMAC rubber can beused preferably. Vulcanized rubber is more preferably used in thepresent invention.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE shows a semi-sectional view of the damper relating to theconfiguration of the embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Next, a configuration of the preferred embodiment of this invention isdescribed by referring to the drawing.

As shown in the FIGURE, a massive body (also called a vibration ring) 2is concentrically arranged on an outer peripheral side of the hub 1mounted on an outer periphery of an end portion of a crankshaft (notshown) which is connected with an internal combustion engine of anautomobile engine or the like, and a gap 3 is arranged between bothparts 1, 2, namely, where an elastic body 4 (also called a rubber ring)is press-fitted into this gap 3 from either direction of the shaft, andthe hub and the massive body 2 are coupled to each other via the elasticbody 4.

The hub 1 is annularly formed from a given metal and integrates an innerperipheral side cylindrical part 1 a to be mounted on the shaft, a diskpart 1 b, and an outer peripheral side cylindrical part 1 c in one body,and the massive body 2 is coupled to the peripheral portion of thisouter peripheral side cylindrical part 1 c via the elastic body 4. Themassive body 2 is annularly formed from a given metal. The elastic body4 is annularly formed from a given rubber-like elastic material(vulcanized rubber). Moreover, endless belts (not shown are entrained oneach of the hub 1 and the massive body 2, which are provided with pulleyparts 1 d, 2 a for communicating rotary torque to each auxiliary machine(not shown).

The elastic body 4 has a stock allowance to be press-fitted and fixedbetween the hub 1 and the massive body 2, however, the arrangement ofonly this stock allowance can cause sometimes a slide between the hub 1and the elastic body 4 or between the massive body 2 and the elasticbody 4 in the direction of a rotation at a time of a heavy loadcondition as described above.

Therefore, in the configuration of this embodiment,polymethylene-polyphenyl-polyisocyanate is interposed between the hub 1and the elastic body 4 at the boundary 5 and also between the massivebody 2 and the elastic body 4 at the boundary 6 respectively as anon-slide agent for substantially increasing a slide torque (a criticaltorque for a slide occurrence) by the means.Polymethylene-polyphenyl-polyisocyanate is applied at least to the outerperipheral surface of the outer peripheral side cylindrical part 1 c ofthe hub 1 and the inner peripheral surface of the massive body 2.

Next, evaluation tests were carried out in order to check the functionand effect by the above configuration and so the contents of the testsare described below. The test conditions were as follows:

A rubber material of the elastic body (NBR compound)

<Compound for Examination>

Nipol DN401 (Nippon Zeon.) 100 (phr) Seast 300 (Tokai Carbon Inc.) 68Haku Enka cc (Shiraishi Kogyo Inc.) 5 ZnO 5 Stearic Acid 1 Antigen AS(Sumitomo Kagaku Kogyou Inc.) 2 Antigen 3C (Sumitomo Kagaku Kogyou Inc.)2 Dioctyl Sebacate 10 Sulfur 1 Sokusinole NBS (Sumitomo Kagaku Inc.) 2Sokusinole TBT (Sumitomo Kagaku Inc.) 1 Sokusinole TS (Sumitomo KagakuInc.) 1 Total 198

Configuration of the torsion damper:

<Shape and Dimensions>

A torsion damper for the above tests was defined to have a shape asshown in FIG. 1, and an outer diameter of 163 mm was adopted.

<Manufacture or Treatment>

The torsion damper shown in the FIGURE was manufactured by the followingprocesses:

a. The non-slide agent was applied to metallic part by spraying

b. Dried in a room temperature (10 minutes)

c. Elastic body was press-fitted between the metallic parts

d. The press-fitted assembly was cleaned (cleaned with methylenechloride)

e. Heated in a constant temperature oven (120° C.×22 hours )

f. Slide torque evaluation test was performed

<Kinds of Non-slide Agents and Method of Machining the Metallic Parts>

As shown in Table 1 below.

<Results>

As shown in Table 2 below.

As shown in the measurement results of this Table 2, it is possible toconfirm that a new assembly could substantially be increased in a slidetorque, and that it was also excellent in heat resistance, durabilityand in corrosion resistance, and further that the slide torque wassubstantially increasable at the initial stage as well as even afterheat-aging, or after an endurance test, etc.

The present invention shows the following effects:

Namely, the damper in accordance with the present invention is a fittingtype damper formed by press-fitting an elastic body of a rubber-likeelastic material between a hub and a massive body from a directionparallel to the shaft, and polymethylene-polyphenyl-polyisocyanate isinterposed as a non-slide agent between the hub comprised of metallicparts and the boundary of the elastic body or between the massive bodycomprised of metallic parts and the boundary of the elastic body, andthus, a new assembly can substantially be increased in a slide torqueand is also excellent in heat resistance, durability, and corrosionresistance, and further, the slide torque is substantially increasableat the initial stage or even after heat-aging, and an endurance test,etc. Therefore, the non-slide agent makes the metallic parts and elasticbody resistant to slides in the direction of the rotation, and permitsto provide a damper product having an excellent vibration dampingperformance even at a time of a heavy load condition.

TABLE 1 Metallic part Name of chemical Nonslide agent working (Name ofmanufacturer) Comparison None None Example 1 Comparison NoneShot-blasting Example 2 Comparison Epoxy type None ADEKA RESIN EP4042(ASAHI DENKA IND., CO.) Example 3 Comparison Phenol type None PHENOLITE2639 (DAINIPPON INK $ CHEMICAL CO.) Example 4 Comparison Water solubleNone ADEKA BON-TIGHTER HUX 232 (ASAHI DENKA IND., CO.) Example 5Urethane type Comparison Vulcanizing None CHEMLOK 252 (ROAD FAR EAST)Example 6 Adhesive type Embodiment 1 Polymethylene None ADEKABON-TIGHTER UCX 853 (ASAHI DENKA IND., CO.) polyphenil- polyisocianate*) *) in the chemical formula, thispolymethylene-polyphenyl-polyisocyanate is a mixture of about 40 weight% of n = 0, about 25 weight % of n = 1, about 10 weight % of n = 2 andabout 25 weight % of n ≧ 3.

TABLE 2 Skid torque (kgf-m):Torque sliding between rubber and a metallicpart by loading in torsional direction Heating 120° C.-22 h (air-heatingin constant temp. oven for reaction of nonslide Condition material)Measuring New After After After steeped in After Condition assembly 100°C.-300 h 120° C.-300 h warm water *1 enduarance test *2 Comparison 50 4234 45 24 Example 1 Comparison 56 52 38 53 26 Example 2 Comparison 54 4638 48 30 Example 3 Comparison 57 50 40 48 32 Example 4 Comparison 56 5241 46 32 Example 5 Comparison 68 58 50 44 48 Example 6 Embodiment 1 8678 74 79 75 *1: After steeped in warm water . . . Skid torque wasmeasured after steeped in 80° C. water for 150 hours. *2: After anendurance test . . . A fixed torsion endurance test was carried out3,000,000 times (rubber temp. = 80° C.) after heat-aging at 100° C. for300 hours, and then, slide torque was measured.

What is claimed is:
 1. A process for manufacturing a fitting type damperformed by press-fitting an elastic body of a rubber-like elasticmaterial between a hub and a massive body from either direction of ashaft, the process comprising the following steps: a) applying anon-slide agent including polymethylene-polyphenyl-polyisocyanatedirectly onto at least one of an outer peripheral surface of an outerperipheral side of the hub or an inner peripheral surface of the massivebody or a surface of the elastic body, and b) press-fitting the elasticbody between the hub and the massive body into contact with the hub andthe massive body to form an assembly with the non-slide agent interposedin direct contact therebetween.
 2. A process for manufacturing a fittingtype damper according to claim 1, wherein the process is furthercomprised of drying the hub or massive body or the elastic body afterthe applying of the non-slide agent.
 3. A process for manufacturing afitting type damper according to claim 1, wherein the process is furthercomprised of heating the assembly to react the non-slide agent after thepress-fitting of the elastic body.
 4. A process for manufacturing afitting type damper according to claim 1, wherein the process is furthercomprised of cleaning the assembly in a solvent to remove dust after thepress-fitting of the elastic body.